# math

posted by
**Anonymous**
.

Determine the exact value of cos^-1 (pi/2). Give a number and an explanaton.

ok so I have a graphing calculator, so i was just wanting to make sure that we plug it in as is? or do we have to change it to put it in the calculator. and im not quite sure what type of explanation to give, do we just say what we plug in and stuff?